Hong Kong Police Quickly Enforce China’s Security Law as Thousands Protest

HONG KONG—Thousands of protesters, unbowed by a sweeping new nationwide-security legislation imposed by China, staged

HONG KONG—Thousands of protesters, unbowed by a sweeping new nationwide-security legislation imposed by China, staged the greatest display of defiance in Hong Kong this yr, with some risking weighty jail conditions to chant slogans of liberation and demand independence.

Hundreds of Hong Kong police officers moved in swiftly to quash dissent and apply the legislation, which gives Beijing significantly higher powers to police the metropolis and punish those accused of subversion and supporting separatism. Police fired tear fuel, pepper spray and drinking water cannons…